In cryptography, a private key password mechanism and a public key password mechanism are used to provide security, ensure integrity and non-repudiation of identity information in communications, and resist identity impersonation attacks. In a public key infrastructure, identity authentication is achieved mainly using digital signature technology and public key password mechanisms. Common digital signature algorithms include RSA algorithms, ECC algorithms, DSA algorithms, EIGamal algorithms, etc. These algorithms provide security using classical authentication techniques based on computing complexity, which may be cracked or otherwise compromised when used in quantum computing and cloud computing environments.
Quantum cryptography is a product of quantum mechanics and cryptography, and provides security based on the basic principle of quantum mechanics, including the uncertainty principle of unknown quantum states, the principle of collapse after measurement and the no-cloning principle. Quantum cryptography provides unconditional security and detectability from eavesdroppers, regardless of computing capability and storage capability of an attacker. However, quantum key distribution protocols currently use a shared key based on a bit error rate. This introduces a problem of insufficient key distribution in large-scale enterprise scenarios, and the shared key negotiation process of a quantum key is greatly affected by external interference and must rely on the bit error rate to determine the output of a quantum key. The yield of actual quantum keys is limited due to the absence of an effective bit error rate estimation method.